Index: llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
===================================================================
--- llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -383,6 +383,9 @@
     foreach(target, all_targets) {
       value = "$value${invoker.value}($target)\n"
     }
+    if (all_targets == []) {
+      not_needed(invoker, [ "value" ])
+    }
     values = [ "${invoker.key}=$value" ]
   }
 }